DE102018106744A1 - USE TO REDUCE A LACK OF THE APPEARANCE OF A WELD IN THE INJECTION MOLDING - Google Patents

Abstract

A molding and method of forming the part are provided by the present disclosure. The molding defines adjacent outer surfaces and includes at least one weld line extending between adjacent outer surfaces. The molding includes an insert disposed on the weld line and extending at an angle between the adjacent outer surfaces. The insert serves to reduce the visibility and / or mechanical impact of weld lines in moldings.

Description

TERRITORY

The present disclosure relates to a method of manufacturing a part, and more particularly, to an apparatus and method for reducing the appearance of surface weld lines formed in a molding process such as injection molding.

GENERAL PRIOR ART

The explanations in this section merely provide background information pertaining to the present disclosure and are not necessarily prior art.

Injection molding is a common method of manufacturing parts, such as automotive interior parts. Injection molding generally involves heating a polymeric / plastic material (eg, thermoplastic) in the form of granules to produce a molten material. This molten material flows through the injection molding line and is injected through one or more flow fronts to fill a mold. When the molten material is within the mold, it cools and solidifies to form a desired part shape (which is the shape of a void or voids within the mold).

In an injection molding process, a quality and / or surface appearance problem arises for the consumer and / or the manufacturer when the molten materials combine within a mold cavity. In particular, an interruption in the molecular orientation of the molten materials may occur so that a line, notch, and / or color change may appear and form what is commonly referred to as a weld line, an example of which is shown in FIG 1 is shown. The position of the weld line usually occurs at locations where the molten material does not fully bond or at which there are holes or weak points of various flow fronts of molten material. Welding lines can cause weaknesses in the molding, wherein the strength of the weld line can be from 10-90% of the molten materials. With a reduction in strength, when the location of the weld line is stressed, it can cause undesirable breakage of the part.

Common solutions for reducing weld lines include induction heating or "e-mold" wherein the surface of the injection mold is placed in a superheated condition to promote better bonding at the weld line locations. However, these solutions can be costly.

The undesirable appearance and structural problems associated with weld lines in moldings are an object of the present disclosure.

SUMMARY

In one form of the present disclosure, a molding is provided that defines adjacent exterior surfaces that include at least one weld line extending between the adjacent exterior surfaces. An insert is disposed on the weld line and extends at an angle between the adjacent outer surfaces. Generally, the insert is designed to enhance molecular and fiber alignment to reduce the severity of the appearance line and / or mechanical properties.

In one form, the insert is defined by a reverse S-cross section geometry. In other forms of the present disclosure, the insert may be a polymeric material, the molded article may be a single material, the molded article comprises at least two polymers, and the insert is a material of one of the at least two polymers and the molded article comprises at least two polymers and the insert a material that differs from the at least two polymers. In another form, the molding includes a plurality of weld lines and a corresponding plurality of inserts disposed on the plurality of weld lines, each insert extending at an angle between the adjacent outer surfaces of the molding. In yet another form, the molding defines a thickness at the weld line and the insert extends through at least 90% of the thickness. The molded part can also be fiber-reinforced.

In another form of the present disclosure, a method of forming a part is provided. The method includes placing an insert at an angle within a mold cavity, sending a quantity of molten resin through the mold cavity to form a first melt front, and sending a further amount of molten resin through the mold cavity to a second melt front form, wherein the first melt front meets at a weld line on the second melt front and flows each front along opposite sides of the insert. In one form, the mold cavity defines opposed inner surfaces and the insert is disposed at an angle between the inner surfaces at the weld line. An end to the Insert may be fixedly disposed on one of the opposite inner sides and another end of the insert flows within the mold cavity. Further, a plurality of inserts may be disposed at an angle within at least one mold cavity, and a plurality of molten resin quantities are sent through the mold cavity to form a plurality of enamel fronts, and the plurality of enamel fronts meet at a plurality of weld lines on adjacent enamel fronts and each adjacent fronts flows along opposite sides of each insert. In one form, the insert defines a material having a glass transition temperature that is greater than or equal to a glass transition temperature of each of the amounts of molten resin.

In yet another form of the present disclosure, a method of injection molding a part is provided. The method includes placing an insert at an angle within a mold cavity, injecting a quantity of molten resin through the mold cavity to form a first melt front, and injecting another amount of molten resin through the mold cavity to a second melt front with the first melt front at the insert meeting the second melt front and each front flowing along opposite sides of the insert.

These various moldings, inserts, and methods may be employed individually or in any combination as set forth herein while remaining within the scope of the present disclosure.

Other uses will be apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.

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• 1 eine perspektivische Ansicht eines Formteils ist, das eine sichtbare Schweißlinie gemäß dem Stand der Technik aufweist;
• 2A eine progressive Querschnittsansicht ist, die eine Schweißlinie veranschaulicht, die in einem Formgebungsverfahren gemäß dem Stand der Technik gebildet wird;
• 2B eine progressive Querschnittsansicht ist, die eine Schweißlinienbildung unter Verwendung eines Einsatzes, der gemäß den Lehren der vorliegenden Offenbarung hergestellt ist, veranschaulicht;
• 3A eine Querschnittsdarstellung eines simulierten durchschnittlichen größeren Moduls durch eine Schweißlinie gemäß dem Stand der Technik ist;
• 3B eine Querschnittsdarstellung eines simulierten durchschnittlichen größeren Moduls durch eine Schweißlinie ist, die einen Einsatz gemäß den Lehren der vorliegenden Offenbarung aufweist; und
• 4 ein Ablaufdiagramm ist, das ein Verfahren zum Bilden eines Teils veranschaulicht, das einen Einsatz gemäß den Grundsätzen der vorliegenden Offenbarung aufweist.

In order that the disclosure may be well understood, various forms thereof will now be described by way of example, with reference to the accompanying drawings, in which:

• 1 Figure 3 is a perspective view of a molding having a visible welding line according to the prior art;
• 2A Fig. 3 is a progressive cross-sectional view illustrating a weld line formed in a prior art molding process;
• 2 B 3 is a progressive cross-sectional view illustrating a weld line formation using an insert made in accordance with the teachings of the present disclosure;
• 3A Fig. 3 is a cross-sectional view of a simulated average larger module through a weld line according to the prior art;
• 3B Figure 3 is a cross-sectional view of a simulated average larger module through a weld line having an insert according to the teachings of the present disclosure; and
• 4 FIG. 10 is a flowchart illustrating a method of forming a part having deployment in accordance with the principles of the present disclosure.

The drawings described herein are for illustration only and are not intended to limit the scope of the present disclosure.

DETAILED DESCRIPTION

The following description is merely exemplary in nature and is not intended to limit the present disclosure, patent application, or uses. It is understood that in all drawings, corresponding reference numerals indicate the same or corresponding parts and features.

Referring to 2A and 2 B is a molding according to the prior art ( 10 ) compared with a molded part ( 20 ) according to the teachings of the present disclosure. In each of these figures, steps A through D illustrate progressive movement of molten materials within a mold over time. In particular and with reference to FIG. 2A involves a molding process (eg, injection molding) of multiple flow fronts of molten materials 11a and 11b that flow together to form a cavity 12 to fill. The molten materials 11a and 11b flow toward each other in the direction of the arrows shown, the arrows representing the fronts of each of the molten materials 11a / 11b. When the mold cavity 12 filled in step D, the molten materials combine 11a and 11b to form a line, a notch, and / or a color change that serves as a weld line 13 referred to as. Even as a single welding line 13 is shown, multiple weld lines may occur in the molding 10.

Referring now to FIG. 2B contains the molding 20 adjacent outer surfaces according to the following disclosure 22 and 24 (Step D) and includes at least one weld line 26 extending between the adjacent outer surfaces 22 and 24 extends. The molding 20 includes a novel insert 30 who is at the weld line 26 is arranged and at an angle between the adjacent outer surfaces 22 and 24 of the molding 20 extends. In this form defines the use 30 a reverse S-cross-sectional geometry, however, it should be understood that other geometries for an insert extending at an angle between the adjacent outer surfaces 22 and 24 can be used while remaining within the scope of the present disclosure. Any angle can be used, provided the use 30 acts to reduce the visibility and / or mechanical action of weld lines of moldings, and therefore the angle illustrated herein is exemplary only. Further, a profile of insert 30 (formed in and out of the cross section of FIG. 1B and along a surface of the molding 20 would be) a surface contour of the final molding 20 to.

As illustrated in the forming steps A to D, when molten materials 32a and 32b to each other and to use 30 flow, each of the materials flows 32a and 32b along opposite sides of the insert 30 as shown by the smaller arrows on the fronts. With this flow dynamics within the mold cavity 25 near the insert 30 causes the use 30 in that a molecular and fiber orientation is improved. Consequently, through the use of the insert 30 the severity of the weld line 26 reduced, or in other words, the visibility of the weld line 26 on the outer surfaces 22 and 24 reduces and / or the mechanical effect of the weld line 26 is reduced.

In one form is the use 30 a polymeric material, such as a thermoplastic or thermoset. The molding 20 may be a single polymeric material or the molded part 20 may be at least two polymers, wherein the use 30 a material of one of the at least two polymers. Alternatively, if the molding 20 At least two polymers may be used 30 a material that differs from the polymers of the molding 20 different. It is also understood that a variety of uses 30 at a plurality of weld lines within the molding 20 may be used while remaining within the scope of the present disclosure. The molding 20 can also be fiber reinforced. In one form, the mission defines 30 a material having a glass transition temperature greater than or equal to a glass transition temperature of each of the molten materials 32a and 32b. General is the use 30 made of a material that matches the final molding 20 melts again to homogenize as much as possible, the appearance of its surface and / or any effect on mechanical properties of the final molded part 20 to reduce. In one form, the use can 30 be produced / formed by a 3D printing process. Alternatively, the insert 30 may be self-formed.

As further in 2 B represented defines the molding 20 a thickness T at the weld line 26 , In one form, the insert extends 30 by at least 90% of the thickness T. It is understood, however, that the use 30 may extend through different thicknesses, which may be less than or greater than 90%, while remaining within the scope of the present disclosure.

In accordance with a method of the present disclosure, the insert is 30 at an angle between opposite inner surfaces 34 and 36 of the mold cavity 25 arranged (step A). The use 30 may be secured by means of a tooling feature (eg, notch, not shown) or may be formed on one or both of the opposing surfaces prior to molding using other means 34 / 36 be secured. In one form is the use 30 firmly on one of the opposite inner sides 34 / 36 arranged and another end of the insert 30 flows inside the mold cavity 25 , Alternatively, the insert 30 may be completely within the mold cavity 25 flow, resulting in a weld line 26 which depends on a flow dynamics of each of the molten materials 32a and 32b emotional.

Referring now to 3A and 3B becomes the average major module of part 10 without an insert with an average major module of the part 20 compared with an insert 30 using Computer Aided Engineering (CAE) simulations. As in 3A shown, it is obvious that the welding line 13 has a much lower average main module and a more visible weld line on the outer surfaces of the molding 10 leads. As in 3B shown increases the presence of an insert 30 the average main module at the weld line 26, thus resulting in a less visible weld line on the outer surfaces and stronger mechanical properties of the molded part 20 leads.

Referring now to 4 For example, a method of forming a part according to the teachings of the present disclosure is schematically illustrated. As shown, an insert is at an angle within a mold cavity. Then, an amount of molten resin is passed through the mold cavity to form a first melt front, and then another amount of molten resin is passed through the mold cavity to form a second melt front, with the first melt front at one melt line to the second Melting front meets and each front flows along opposite sides of the insert. The process may be any molding process and is injection molding in one mold. In this case, the molten resin is injected through the mold cavity.

Further, a plurality of inserts may be used within the mold cavity, each disposed at an angle within the mold cavity. With the plurality of inserts, a plurality of amounts of molten resin are sent through the mold cavity to form a plurality of enamel fronts. The plurality of enamel fronts meet adjacent melting fronts at a plurality of weld lines, and each fronts flows along opposite sides of each insert.

In any of the methods contemplated herein and as set forth above, the molten resin may be a single polymeric material or various polymeric materials may be used to form a single molded article. It will be understood that variations in the molten resin materials and use are possible and contemplated as being within the scope of the present disclosure.

The placement of the insert within a mold cavity can be determined either during tool testing and / or CAE simulations.

The description of the disclosure is merely exemplary in nature, and thus, variations that do not depart from the substance of the disclosure are intended to be within the scope of the disclosure. Such variants are not to be regarded as a departure from the spirit and scope of the disclosure.

Claims (15)

A molding defining adjacent exterior surfaces and including at least one weld line extending between adjacent exterior surfaces, the molding comprising: an insert disposed on the weld line and extending at an angle between the adjacent outer surfaces. Molding after Claim 1 wherein the insert defines an inverted S cross-sectional geometry. Molding after Claim 1 or 2 wherein the insert is a polymeric material. A molding according to any one of the preceding claims, wherein the molding is a single polymeric material. Molding after Claim 1 to 3 wherein the molding comprises at least two polymers and the insert is a material of one of the at least two polymers. Molding after Claim 1 to 3 wherein the molding comprises at least two polymers and the insert is a material different from the at least two polymers. A molding according to any one of the preceding claims, wherein the molding defines a thickness at the weld line and the insert extends through at least 90% of the thickness. Molding according to one of the preceding claims, wherein the molded part is fiber-reinforced. A method of forming a part comprising: Placing an insert at an angle within a mold cavity; Passing a quantity of molten resin through the mold cavity to form a first melt front; and Passing a further amount of molten resin through the mold cavity to form a second melt front, wherein the first melt front meets the second melt front at a weld line and each front flows along opposite sides of the insert. Method according to Claim 9 The method comprises injection molding. Method according to Claim 9 or 10 wherein the mold cavity defines opposed inner surfaces and the insert is disposed at an angle between the inner surfaces at the weld line. Method according to Claim 11 wherein one end of the insert is fixed to one of the opposed inner sides and another end of the insert flows within the mold cavity. A method according to any one of the preceding claims, wherein both amounts of molten resin are the same polymer material. A method according to any one of the preceding claims, wherein each of the amounts of molten resin is a different polymer material. The method of any one of the preceding claims, wherein the insert defines a material having a glass transition temperature which is greater is equal to or greater than a glass transition temperature of each of the amounts of molten resin.

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